Ehm... lolwut? Lowest DPS? Proves, please. Because it's bullsh*t. Especialy with how "Infuriate" and the relative skills works.
Lowest APM - is bad, agree, but in the same time it makes the job incredibly easy to play even if you never played tanks before.
Party wide buffs? Namely? Please insert your answer with particular numbers here and, pray tell, what he doesn't benefit from. More than that all he needs is in his kit: 100% crit, 2 healing abilityes (one of them also increasing the amount of healing recieved) + 1 standart tanking healing skill in the combo.
No interactions with other party members? Have you ever hear or used the "Shake it off" skill?
OT mitigation? He was NEVER the one to mitagate damage, the job was basicaly the pounds of beef with the axe, that goes trough the enemies and HEALS (by self, let me mind you) the damage it takes instead of mitigation. And with that being said he has "Raw intuition" - very short CD 20% mitigation from ALL sources, "Rampart" - standart tanking mitigation for 20% on standart CD, "Vengeance" - 30% mitigation an not so long CD that also DAMAGES everyone who hits you, "Thrill of battle" - up 20% of your health and heal for the same amount, basicaly it's 20% of your HP shield that also INCREASES the healing recieved from all sources, "Equilibrium" - fat-ass healing of 1200 potency that can be 1440 potency under "Thrill of battle" effect and last, but not least - "Shake it off" - the PARTY WIDE SHIELD, that gives all 12% of your max. HP of shield, that can reach 18% of your HP (more than the DRK party shield, let me mind you).
You still think that he's underpowered??!! HELL NO. Job's in the perfect position now as the tank, that can be easily learned by anyone with GREAT mitigation and damage.
Now THIS reply is based on numbers and not BIASed, because my favorite tank will and ever will be PLD and DRK. I find WAR to simple to interest me for long, but still he's to efective to not level him up.